It was on 31st August 1914 that Oldham Corporation started a bus service from Grains Bar to Denshaw. The genesis of this service lay in the extension of the tram network Oldham had started bus operation (from the Town Hall to Coppice) on 12th May 1913 - see the gallery on the A service. This service only ran on weekdays and the popularity of the hills at Grains Bar led to the buses being used to run a Moorside to Grains Bar service from 16th May 1913 at times when there was a demand. This was usually on early closing day (Tuesday) and at weekends. At busy times two buses would be used.

The tram route extension from Grains Bar to Moorside, which was the highest tram route in the country with a terminus at around 1150 feet above sea level, opened on 4th June 1914 which made the bus service unnecessary, but a bus was soon deployed on the new route to Denshaw from 31st August 1914. However, the Great War brought about different needs and the service last ran on 27th August 1916.

Denshaw was served by North Western buses from 1925, but Oldham Corporation did not start to run to Denshaw until 15th April 1927. A new service was introduced from Oldham to Halifax. This was operated by Oldham Corporation and North Western and in agreement with Halifax Corporation. The initial service ran every 90 minutes but this may have been reduced for the winter as there is a record of a complaint about the reduced winter service.

On 26th July 1928 Oldham Corporation Tramways Committee approved a Heads of Agreement with North Western whereby Oldham’s operation would be restricted to a local service from Oldham to Denshaw. The timing avoided a dispute with West Riding County Council who had complained that Oldham’s operation on the route was unauthorised in the WRCC area apart from a short stretch which was presumably that in Saddleworth. They were threatening to institute proceedings for operation in excess of statutory powers but the North Western agreement allowed Oldham to say they were ceasing operation anyway. Oldham buses last ran to Halifax on 28th July 1928, just two days after the agreement was signed.

The Halifax service had been given the route letter ‘H’ in line with Oldham’s practice of using letters for bus services. Letters were allocated in order as new services were introduced and it is just a coincidence that H is the first letter of Halifax. The route letter continued to be used for the Oldham to Denshaw service until 8th September 1957, when a reorganisation of services saw the introduction of a modified service 6 running from Chadderton Burnley Lane to Denshaw and this H service was withdrawn.

One unusual feature of the timetable was the lack of a morning service to Denshaw. For example, from Denshaw there were four morning peak journeys up to 0820, then there was a bus at 1030 and the next was at 1250 after which the service ran every 30 minutes.